Location: Bioproducts Research
2018 Annual Report
Objectives
The demand for agricultural feedstocks is growing as global demand for food is ever increasing and efforts mount to create alternatives to petroleum products that feed global warming. The goal of this project plan is to use biopolymers to develop sustainable technologies and bioproducts that will benefit the U.S. and that will not negatively impact food reserves. This plan highlights the use of nonfood fibers and crop waste to create new bioproducts and help improve the efficiency in utilizing agricultural commodities via the following objectives:
Objective 1: Enable, from a technological standpoint, new commercial value-added biobased materials.
a. Utilize conventional and novel processing technologies to produce and characterize nanofibers from biopolymers and investigate potential applications.
b.Utilize biopolymers to encapsulate/deliver beneficial soil microbes that improve crop production.
Objective 2: Enable new commercial materials based on biopolymers and biobased fillers.
a. Develop fiber-reinforced composite materials.
b. Develop value-added bioproducts from torrefied crop waste.
c. Develop value-added bioproducts from almond, grape and citrus waste.
Approach
The overarching approach will be to provide data, technology and prototypes that will not only result in novel bioproducts but also address important agricultural needs including the need for higher crop production, the need for more sustainable farming practices, the need for alternatives to petroleum-based products and the need for new innovations such as nanotechnology. The first approach is development of composite materials that encapsulate beneficial microbes to be used to reduce the inputs of conventional fertilizers and petroleum-based pesticides. A co-development as part of this approach is production of humic acid from renewable resources such as torrefied crop waste to augment soil health. Humates will be used as soil amendments to improve soil fertility and crop production. Also, nanofibers from aqueous solutions of biopolymers will be made and characterized by developing new processes to make nanofibers from a wide array of biopolymers. Bioproducts made using the nanofibers will include controlled-release devices and sensors.
Objective 2 is aimed at developing bioproducts from nonfood agricultural products, namely plant fibers and crop waste. The group will apply expertise in dispersing plant fibers in biopolymer matrices and in inorganic binders. The anticipated bioproducts developed in Objective 2a include compression molded food service products containing more than 60% fiber using biopolymers as binders. We will also create lightweight rigid foam products by dispersing plant fibers in inorganic binders including Portland cement and gypsum.
California has one of the most diverse agricultural industries in the world and ranks first in production in terms of cash receipts ($43 billion), but also leads in the output of crop waste and residues. Diverse agricultural byproducts such as almond hulls, grape pomace, citrus peel waste, etc., which are concentrated at processing plants and often carry a cost for disposal, will be converted into higher value products. Objectives 2b, and 2c specifically address this need. The anticipated products include black filler for PET plastics and pelletized coal dust made using inexpensive biopolymer binders such as citrus waste and gums from almond hulls. Other bioproducts include essential oils and antioxidants extracted from seeds processed from grape pomace.
Progress Report
Sub-objective 1a: In collaboration with colleagues from Brazil, ARS researchers in Albany, California, created ceramic nanofibers with the silica compound tetraethyl orthosilicate (TEOS). The nanofibers were characterized, showing novel structures and properties, and the data was compiled for the publication of two manuscripts. The first manuscript reported the production of nano- and submicrometric silica and spinel-ferrite fibers using the solution blow spinning (SBS) method. A pseudo-core-shell method to produce silica fibers with large surface areas was also reported. The silica fibers had mean diameters ranging from 280 nanometer (nm) to 640 nm and specific surface areas ranging from 140 m2/g to 630 m2/g. Spinel-ferrite fibers of nickel ferrite and nickel-zinc ferrite had mean diameters of 180 nm. The nanofibers had a cotton-like morphology and were produced at higher output rates than those achieved by other current spinning technologies. The second publication is in preparation.
Sub-objective 1b: Based on field trials with microbes encapsulated for release in soils, it was determined that the encapsulation matrix would only be effective if it was loaded with microbes that were active in the root zone of crops. For now, the most effective application method appears to be adding the formulation as a liquid product that can be injected through the drip or sprinkler system. An ARS partner under a Cooperative Research and Development Agreement (CRADA) is conducting field trials with farmers to demonstrate the effectiveness of microbial treatments. Initial results appear promising and further trials are being planned.
Sub-objective 2a: Cellulose fiber foam has been produced commercially for many years. Cellulose fiber foam is a sustainable material made of plant fiber. The traditional process begins with a foam with a very high-water content and results in substantial shrinkage. ARS researchers in Albany, California, developed a method of producing a fiber foam using minimal amounts of water. Adding polylactic acid fiber to the formulation minimized the shrinkage. The result is a foam with very little shrinkage that can be dried more efficiently compared to traditional cellulose fiber foam. Since the foam has a relatively low water content, the foam can be easily conveyed into molds and dried with very little shrinkage. The final product is a rigid foam that can be compressed into finished articles such as plates or used as a moldable foam insulation.
Sub-objective 2b: Funding has been procured by key stakeholders to obtain torrefaction capabilities at our facility. Torrefaction is a mild form of pyrolysis at temperatures typically between 200 and 320 degrees Celsius. Torrefaction changes biomass properties to provide a better fuel quality for combustion and gasification applications. A torrefier has been built and installed in one of the campus out buildings. The ARS team also obtained an attritor, a type of grinder in which particles suspended in a liquid are moved by paddles and are ground as they collide with each other or with the grinding medium to mill torrefied almond and walnut shells to approximately 0.04 millimeters (mm). Torrefied almond shells added to recycled polypropylene to make a masterbatch of material to supply to commercial producers of slip sheets; i.e. the packaging sheets used between shipping boxes. The mechanical and functional properties of the plastics filled with torrefied shells have been evaluated by a commercial partner to help optimize the process.
In other torrefaction work, the effects of inorganic species on the torrefaction kinetics of almond and walnut shells between 240 and 300 degrees Celsius (C) were determined using thermogravimetric analysis. Raw shells were leached with water at 80 degrees C for 2 hours to remove 80 and 86 percent of potassium from raw almond and walnut shells, respectively. During each isothermal kinetics run, the leached almond shells had higher mass yields than the raw shells, even at 240 degrees C. In comparison, the raw and leached walnut shells had comparable mass yields at 240 degrees C with the mass yields becoming different at higher temperatures. This was due to the higher concentration of 0.89 percent weight by weight (w/w) potassium in almond shells compared to 0.08 percent w/w in walnut shells since potassium had been shown to catalyze decomposition of biomass. The two consecutive parallel reactions kinetic model exhibited the best fit to experimental data. However, the one-step reaction model gave the best predictions of mass yields for torrefaction of raw almond shells in a fixed-bed reactor.
Accomplishments
1. Self-assembled antibiotics, a safe and sustainable solution to prevent drug-resistant bacteria. Worldwide deaths resulting from drug-resistant bacteria are trending upward and persistent antimicrobials currently used in consumer products and agriculture contribute to this problem by causing collateral antimicrobial resistance. There is thus a serious need to develop new antimicrobials that can circumvent antibiotic resistance mechanisms and exhibit a limited post-use lifetime. In collaboration with a commercial partner, ARS researchers in Albany, California, invented a new class of antimicrobials designed to circumvent antibiotic resistance via formation of reversible, self-assembled antibiotics. Owing to their reversible nature, these antimicrobials are designed to fall apart into nontoxic subcomponents after disposal, meaning that they do not have a long-term negative impact on the environment. This research could markedly impact antibiotic products and has been selected as a winning additive by the Green Chemistry & Commerce Council’s (GC3) Preservatives Project in an international challenge to develop safer commercial preservatives.
2. Sugar extract from almond hulls for novel uses. Almond hulls have a high sugar content and are mainly used as feed for dairy cattle. However, the dairy industry is decreasing in size and there is a need to develop new applications for the sugar-rich hulls. ARS scientists in Albany, California, and Tucson, Arizona, extracted sugars from almond hulls and used these extracts to make food formulations for bees. The key is to extract the bitter polyphenols from the sugar extracts to make the formulations palatable to the honeybees. These sugar formulations are aimed to create alternative markets for the hulls while helping both the almond and bee industries.
3. Improved process for making degradable food containers. There is a major trend towards making single-use food containers from renewable materials that compost easily. Traditionally, the cost of agricultural materials is competitive with plastics, but the processing costs have been significantly higher. ARS scientists in Albany, California, developed a novel process for making food containers from plant fiber composites that degrade quickly. The containers are compression molded in only a few seconds and compost more readily than paper products. A patent application has been submitted for this invention and a commercial partner is developing commercial products. This research improves the sustainability of the single-use food container industry, providing new degradable and sustainable options.
Review Publications
Parize, D.D., Oliveira, J.E., Williams, T.G., Wood, D.F., Avena-Bustillos, R.D., Klamczynski, A., Glenn, G.M., Marconcini, J.M., Mattoso, L.H. 2017. Solution blow spun nanocomposites of poly(lactic acid)/cellulose nanocrystals from Eucalyptus kraft pulp. Carbohydrate Polymers. 174:923-932.
Farias, R.M., Severo, L.L., Costa, D.L., Medeiros, E.S., Glenn, G.M., Santata, L.N., Neves, G., Kiminami, R.H., Menezesa, R.R. 2018. Solution blow spun spinel ferrite and highly porous silica nanofibers. Ceramics International. 44(9):10984-10989. https://doi.org/10.1016/j.ceramint.2018.03.099.
Vargas-Torres, A., Palma-Rodriguez, H.M., Berrios, J.D., Glenn, G.M., Salgado-Delgado, R., Olarte-Paredes, A., Prieto-Mendez, J., Hernandez-Uribe, J.P. 2017. Biodegradable baked foam made with chayotextle starch mixed with plantain flour and wood fiber. Journal of Applied Polymer Science. 134(48):45565. https://doi.org/10.1002/app.45565.
Liu, F., Saricaoglu, F., Avena-Bustillos, R.D., Bridges, D.F., Takeoka, G.R., Wu, V.C., Chiou, B., Wood, D.F., McHugh, T.H., Zhong, F. 2018. Preparation of fish skin gelatin-based nanofibers incorporating cinnamaldehyde by solution blow spinning. International Journal of Molecular Sciences. 19(2):618. https://doi.org/10.3390/ijms19020618
Liu, F., Saricaoglu, F., Avena Bustillos, R.D., Bridges, D.F., Takeoka, G.R., Wu, V.C., Chiou, B., Wood, D.F., Mchugh, T.H., Zhong, F. 2018. Antimicrobial carvacrol in solution blow-spun fish-skin gelatin nanofibers. Journal of Food Science. 83(4):984-991. https://doi.org/10.1111/1750-3841.14076.
